Tuesday, September 8, 2009

What is Ethernet ?

In this section you will learn about the lan terminology, basic ethernet networking overview, a general introduction to LAN, introduction to IEEE, lan topologies, wan standards. You can also find these categories in this site such as network tutorials, computer networking guide, what is networking, tech study guides, topologies, what is data recovery, wireless communication, computer interview questions and network certification. The IEEE standards have been developed by the International Standards Organization (ISO). The Institute of Electrical and Electronic Engineers (IEEE) in 1985 produced a series of standards for the Local Area Networks, which are called IEEE 802 standards.

These standards have been accepted widely throughout the IT world. One of the IEEE 802 standards, the IEEE 802.3 is known as “Ethernet”. Ethernet is the most widely used LAN technology. Ethernet was developed by Xerox corporations in 1972 and it was the first LAN.
According to the ISO standards allows manufactures to produce the devices and equipments, which are guaranteed to operate anywhere.

The Ethernet in its simplest form uses a passive bus that operates at 10 Mbps. The bus is formed from the co-axial cable, which connects all the PCs in the LAN.

A single LAN may have 1024 attached computers, although in the real practice most LANS have fewer computers than this number. One or more segments of the co-axial cable are attached to end to end to create the Ethernet Cable Segment. Each segment is terminated by 50 ohm resistors.

In today’s IT world the reliable and timely access to the information has become vital. Today coworkers thousands of miles apart from each other can share data, voice, video etc with the fractions of seconds. Similarly a larger number of the coworkers can review the research data simultaneously. The Internet allows businesses to share information and resources with their customers.

Ethernet is a communication protocol that is embedded in software and hardware devices that intended. Ethernet has become the standard computer networking protocol with the help of the Xerox, Intel and Digital

A basic LAN consists of the following components.
• Two or more computers.
• Network Interface card or LAN Card in each PC.
• Ethernet cable (Cat5, UTP/SPT) cable to connect the two computers.
• A hub, switch or router to route or direct the network traffic.
• Software for the communication/computer networking.

A network interface card (NIC) is attached and installed in each PC and is assigned a unique address. An Ethernet cable is used to connect two computers; Ethernet cable has RJ45connectors at both ends. There can be two scenarios 1. Two computers can directly connect with each other or 2. Each computer is directly connected with the hub/switch and hence communication occurs in the network. The hub or switch acts as relay.

Computer Network can be wireless. Despite of using Ethernet cable for the communication, Wireless Network Interface cards use radio waves to communicate with the wireless switch or hub. A small antenna is used in the wireless NICs, switches and hubs. Although the wireless networks are more easy to use as compared to the cabled networks, but more configurations and extra care is required to setup and run a wireless network.

The alternate technologies to Ethernet are “Token Ring”, which is used in the Ring Topologiesnetworks. Token Ring is designed by the IBM and ATM. In ATM networking, devices are connected with each other over a very large distance (thus forms the WAN), and behaves like LANs.

Ethernet is a well established and widely used network standard for small to medium sized Ethernet networks as well as for other networks. Ethernet has been used over the 3 decades and forms a very excellent networking/communication environment. Ethernet TermsEthernet follows a simple set of rules. To understand these rules its important to understand the
following terminology.
• Node – The devices that are attached to the segments are nodes.
• Frame – The nodes (computers or network devices) communicates in the form of short
messages that are known as frames. The frames are chunks of information with variable size.
• Segment – A single shared medium is known as a Ethernet segment.
• Medium – The Ethernet devices are attached to a common medium. The frames of the data
travel along with that medium. This medium can be coaxial cable. Today most commonly used
communication mediums are UTP/STP cable, fiber optic cables.

Frames are analogous in human language. We have some rules for constructed the sentences.

Ethernet protocol specifies a set of rules for constructing the frames. The frames length varies.
Each frame must contain source and destination address for the identification of the recipient and the send of the message. The nodes can be uniquely and easily identified. Each Ethernet devices must have a single unique address.

Compute networking standards has brought a revolution in the network computing and it made the communication very easy and standarized. Now every computer and networking devices has to to follow the same standard to communicate with each other.

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